1. Field of the Invention
The present invention relates to a laminated non-woven fabric including a fibrous layer obtained by using a fiber melting or softening at 120° C. or less, and a manufactured article obtained by using the laminated non-woven fabric.
2. Description of Related Art
The non-woven fabric using the polyolefin thermal adhesive fiber is favored because of such characteristics as the tender hand feeling and the high non-woven fabric strength, and is used for such hygienic materials as the disposable diaper and the menstrual article. Generally, the heat treatment method used to manufacture the thermal adhesive fiber into the non-woven fabric may be substantially categorized into two methods as follows: the hot air-through bonding process utilizing the suction band dryer or the suction dryer, and the point thermal compression bonding process utilizing the so-called embossment machining in which a web is introduced between a heated embossing roll having multiple projections and a flat roll (smoothing roll) to obtain the non-woven fabric. Particularly, compared with the hot air-through bonding process, the latter point thermal compression bonding process has more excellent producibility, and therefore, is also advantageous in the cost. However, as the recent tendency, the non-woven fabric of the surface material used for the hygienic material obtained through the point thermal compression bonding machining is required to have more tender hand feeling. Therefore, the industry is conducting research on a method for constraining the machining temperature to be low or a method for reducing the area ratio of the point thermal compression bonding portion.
In the method for constraining the machining temperature to be low, the thermal bonding in the non-woven fabric becomes insufficient, the non-woven fabric strength is inadequate or the interlayer peeling is caused, which becomes the reason for generating the fluff, so the problem of fluff resistance deterioration exists.
On the other hand, in the method for reducing the area ratio of the point thermal compression bonding portion, although the degree of freedom of the fiber is increased, and the hand feeling is improved, the interlayer peeling is generated easily and the strength of the non-woven fabric becomes insufficient, so the fluff resistance deterioration tends to exist.
Additionally, as the non-woven fabric having the tender hand feeling, in a tri-layered construction of a layer formed of a polyethylene terephthalate long fiber between layers formed of the long fiber (core-sheath conjugate) of polyethylene terephthalate as a core component, and high density Polyethylene (PE) as a sheath component, it is proposed that, the whole of the non-woven fabric is formed into the laminated non-woven fabric by the local point thermal compression bonding (for example, referring to patent document 1).
According to the construction, the intermediate layer of the polyethylene terephthalate long fiber includes the resin component with the melting point higher than that of the fiber of the upper layer and the lower layer, so even if the intermediate layer is subject to the point thermal compression bonding, the fiber in the intermediate layer is bonded to each other less, and the fiber becomes easily and freely movable, so that the softness of the non-woven fabric is maintained. However, on the other hand, it is difficult to obtain sufficient strength of the non-woven fabric, and if it is intended to perform high temperature treatment on the fiber in the upper layer and the lower layer in order to obtain the strength, it is easy to weld the embossing roll, but the stable producibility (maneuverability) may not be sufficiently satisfied. Furthermore, because the bonding between laminated layers is inadequate, so when the non-woven fabrics are rubbed each other, the peeling between laminated layers is easily generated, and the outcome is that the fluff resistance can neither be sufficiently satisfied.